不同年龄紫穗槐对沙化土壤的改良效应

以毛乌素沙地南缘沙化地不同种植年限的紫穗槐（Amorpha fruticosa）为研究对象，探讨了不同种植年限紫穗槐对沙地的恢复效应。分析了紫穗槐灌丛土壤的机械组成、养分含量以及不同种植年限紫穗槐土壤养分与沙尘粒之间的相关性。结果显示，紫穗槐灌丛的土壤细化程度随着种植年限的增加逐渐增大，表层（0～10 cm）土壤的细化程度为1951年>1976年>1983年>2005年， 1951年种植的紫穗槐的沙尘粒含量达到了4.3%；各种植年份紫穗槐土壤垂直剖面pH值自下而上逐渐降低，表层土壤（0～10 cm）pH值最低，同土层不同年份紫穗槐灌丛土壤pH值基本随种植年限延长而降低；0～20 cm土层中养分含量（除全钾和铵态氮）均出现了不同程度的增加，有机碳、全氮、硝态氮、全磷和速效磷等含量均随着种植年限的增加而增加，铵态氮和全钾含量则无明显规律。

Effects of Amorpha fruticosa on soil physical composition and nutrient content

Taking Amorpha fruticosa with different cultivation ages in Southern Mu Us desert as objectives, a study was made on the physical composition and nutrient content of soil under A.fruticosa, and correlation between soil nutrients and dust particles were analyzed. The results showed that refined degree of soil under A. fruticosa increased gradually with the increasing of A. fruticosa cultivation ages. For example, the refined degree of surface soil (0-10 cm) was 1951>1976>1983>2005, and dust particles content of A. fruticosa planted in 1951 was 4.3%. pH values of vertical soil profile in A.fruticosa decreased from bottom, and pH value of surface soil (0-10 cm) was the lowest. pH values of the same soil layer reduced with the increasing of cultivation ages. All nutrients content (except of total K and NH4+ N) of soil (0-20 cm) increased in varying degrees. The content of organic carbon, total N, NO3- N, total P and rapid available P increased with the increasing of cultivation ages, while there was no apparent regularity in content of NH4+ N and total K.